5 Investigates discovered it's a legal loophole that's helping this firefighter and many other repeat drunken drivers get back in the driver's seat.

Capt. Patrick Ellis was behind the wheel of his truck even though, according to the Massachusetts Registry of Motor Vehicles, he has been caught driving drunk twice and in the most recent case in February he even refused the Breathalyzer.

Ellis was arrested by Westborough police after he drove a tanker truck off a weigh scale while working his part-time job hauling chemicals. Police say Ellis staggered, almost fell over and threw a bottle of vodka into a snow bank.

"I had him count backwards from a hundred, he had a hard time doing that," said Westborough police Officer Domenic Annunziata. "I had him do the one-leg stand, he had a hard time doing that, couldn't maintain his balance. The nine-step walk and turn, he staggered."

In his full-time job Ellis doesn't drive, he rides in the jump seat of Ladder 14 where he's most likely seen the horrible consequences of drunken driving. Police say his most recent arrest is proof he's a danger on the road.

"If someone is intoxicated and they're going to drive a tanker down the Mass Turnpike, they clearly don't care and they don't have any regard for other people," said Officer Annunziata.

5 Investigates discovered a legal loophole that may have helped Ellis get back on road. Because his first OUI was more than 10 years ago, he qualifies for a hardship license even though he refused the Breathalyzer.

Normally, if you refuse the Breathalyzer on a second OUI, state law says your license is automatically suspended for three years.

But that loophole allows second-time offenders like Ellis to get a hardship license with restricted driving hours as long as they enroll in what's called the 24D alcohol program. An interlock device that prevents a car from starting if alcohol is detected is placed in their car, but in many cases the repeat drunken driver is allowed to drive again within weeks of his or her arrest.

According to the RMV, there are 5,438 drivers like Pat Ellis in the 24D program.

Ellis declined to speak with 5 Investigates, but his lawyer, Martin Kane did.

"From a government perspective, you're helping people get on the right path," Kane said. "I think they look at the fact that a person hasn't had a problem like my client in 20 plus years and he should be able to accept responsibility for his actions which is exactly what he did."

Ron Bersani calls the loophole unacceptable. His granddaughter Melanie Powell was killed by a drunken driver in 2003. Melanie's law established tougher penalties for repeat drunken drivers who refuse the breathalyzer.

"According to Melanie's law, which was instituted after the lifetime look back, this should have been a second offense," Bersani said. "He should have lost that license for an extended period of time."

The Boston Fire Department tells said Ellis is one of the most dedicated and hard-working members of the department.

His lawyer said because Ellis' first OUI was on a military base, it's not considered a conviction even though the RMV treats it as a first offense.